1. Field of the Invention
The present invention relates generally to multi-stage turbine pumps. In another aspect, the invention concerns a system for testing the wear resistance of impellers used in multi-stage turbine pumps.
2. Description of the Prior Art
Multi-stage turbine pumps are commonly employed in a variety of different applications. In one application, multi-stage turbine pumps are used as injection pumps for oilfield water flood operations. Frequently, the water pumped by the injection pump to the injection well is produced water that has previously been extracted from a subterranean formation along with oil, and subsequently separated from the oil.
One common problem encountered when using a produced water stream for water flood operations is that the produced water stream can contain small quantities of abrasive materials. Typically, the abrasive materials include minute sand particles which were produced along with oil and water from the subterranean formation. Such small sand particles can be difficult and expensive to entirely remove from the produced water stream. Thus, the produced water pumped to injection wells for water flooding operations inevitably contains at least a small amount of sand particles. These sand particles can cause significant wear on the impellers of a multi-stage turbine pump used to pump the produced water to the injection well. Although there has been much speculation as to which materials and/or coatings are best suited for constructing wear-resistant impellers, there has never been an adequate method for comparatively testing which materials or coatings work best in multi-stage turbine pumps used to pump produced water to injection wells.